Welcome to the Interaction to Next Paint (INP) Troubleshooting Guide. INP is a pending Core Web Vital metric set to replace First Input Delay (FID) in March 2024. This guide is designed to help you understand what INP is, how it differs from FID, and why Google is making this change. You will also learn how to measure and optimize INP using various tools and techniques. Our goal is to provide you with clear and actionable steps for improving your site's user responsiveness, ensuring a seamless experience for your visitors. Let's dive into how you can get ahead of this upcoming change and optimize your site's performance effectively.

Common symptoms indicating issues with Interaction to Next Paint (INP) include:

1. High Interaction Latency: Users may experience noticeable delays after clicking, tapping, or using keyboard events before the browser responds.
2. Input Delays: A significant wait time before the browser starts processing user interactions.
3. Processing Delays: Prolonged execution time for the site's event handling code, resulting in unresponsive or sluggish behavior.
4. Rendering Delays: Extended time taken by the browser to visually render the next paint after a user interaction.

These symptoms can lead to a decrease in overall user satisfaction and site performance.

Identifying and addressing issues with INP involves several steps and tools. Here are detailed solutions to common problems users may encounter:

1. High INP Scores:
   • Step 1: Utilize Google Search Console to identify pages with the worst INP scores. This will help you pinpoint which pages need immediate attention.
   • Step 2: Use Real User Monitoring (RUM) data available in BDA to analyze the Core Web Vital data collected from real user interactions.
   • Step 3: In a lab setting, since FID and INP are not available, use Total Blocking Time (TBT) as a substitute metric. Optimize TBT as it correlates well with INP.
2. Optimizing JavaScript:
   • Step 1: Enable relevant settings that optimize JavaScript loading, parsing, and execution to minimize input and processing delays.
   • Step 2: Focus on reducing TBT scores by addressing specific TBT audits in lab tests.
3. Rendering Delays:
   • Step 1: Optimize the browser’s style recalculations by reducing and simplifying CSS. CSS optimization settings can help by removing unused CSS and minifying the CSS that is used.
4. Identifying Slow Interactions:
   • Step 1: Use Lighthouse's Timespan mode to interact with the page and receive INP-specific audits. These audits can provide insights into which delays are taking the longest and how to address them.
5. Advanced Optimizations:
   • Step 1: Manually remove unused or mostly unused CSS, JavaScript, and plugins to reduce processing delays.
   • Step 2: Minimize the DOM size of your pages to reduce presentational delays.
   • Step 3: Optimize event handling code if it performs extensive work that delays the browser's next paint. Speed up the code or offload tasks to improve responsiveness.

By following these steps, you can effectively troubleshoot and optimize your site’s INP scores.

To ensure optimal performance and prevent issues related to Interaction to Next Paint (INP), it is essential to follow these best practices:

1. Optimize JavaScript Loading: Minimize input and processing delays by optimizing how JavaScript is loaded, parsed, and executed. This can help reduce long tasks that delay the browser's ability to process user interactions.
2. Reduce Total Blocking Time (TBT): In lab tests, focus on reducing TBT scores by addressing TBT-specific audits. A lower TBT score can indicate better responsiveness during the initial page load, which correlates with improved INP.
3. Simplify and Optimize CSS: Reduce and simplify CSS to optimize the browser's style recalculations. Removing unused CSS and minifying the CSS that is used can contribute to lower presentational delays and better overall INP scores.
4. Monitor INP Scores Regularly: Use tools like Big Data Analytics' Real User Monitoring (RUM) data to keep an eye on your INP scores. Regular monitoring helps identify pages with poor INP performance and allows for timely optimizations.
5. Use Web Vitals Chrome Extension: This extension provides real-time INP readings and can help you identify slow interactions on your page. Logging information to your browser's developer console can also offer insights for further optimization.
6. Utilize Lighthouse's Timespan Mode: Conduct audits specific to INP by using Lighthouse's Timespan mode while manually interacting with your page. These audits can reveal opportunities to speed up user interactions.
7. Minimize DOM Size: Reducing the DOM size of your site's pages can help in minimizing delays and improving INP scores.
8. Remove Unused Code and Plugins: Manually remove any unused or mostly unused CSS, JavaScript, and plugins from your site. This can reduce both processing and presentational delays, leading to a better INP score.

By implementing these tips, you can maintain optimal site performance and ensure a responsive user experience.

If you need further assistance with Interaction to Next Paint, please log in via https://support.ezoic.com/ to make use of our dedicated resources for support. We're here to help!